This invention relates to a portable silo or bulk storage system for the storage of free-flowing solid materials such as powders, grains, pellets or the like. For example the system is suitable for the bulk storage of salt, flour, sugar, green coffee, milk powder, corn starch and corn sugar powder, grain feeds, fertilizers, cement, nylon flakes, aluminum hydroxide and numerous resins such as polyester resin, polyethylene, polyvinyl chloride and others. For convenience such materials will be referred to below as "granular" materials.
The object of the invention is to provide an inexpensive and readily portable silo or bulk storage system that will nevertheless be reliable and easy to erect and use in practice. Bulk storage refers to the storage of quantities of the range of 10,000 lbs and up of a granular material. Traditionally such quantities have been stored in permanent, rigid silos which are expensive, bulky, heavy to move from place to place and not generally adapted for use indoors.
A prior proposal for a flexible storage bin is shown in U.S. Pat. No. 3,058,623 issued Oct. 16, 1962 to T. F. Hawk et al.